A programme for Promoting Rainwater Harvesting in the Caribbean

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Caribbean Rainwater Harvesting ProgrammeGrenadaMainland Grenada’s water supply is drawn almost exclusively from surface stream sourceslocated at relatively high elevations so that the distribution network is primarily gravity-fed.The estimated water production ranges between 27,300 m 3 /day (6 MGD) and 31,800 m 3 /day(7 MGD) during the dry and wet seasons respectively. The National Water and SewerageCorporation (NAWASA) claims up to 90% coverage of their distribution network withreliability in service provision that ranges between 85 and 90%. Communities in the extremesouth and north of the island tend to be more water-stressed given their relative location atthe distal ends of the distribution networks, a problem that can be particularly acute duringthe dry season. Demands from tourism and other commercial sectors and urbanization areplacing pressures on the existing production points. In 1998 the Government of Grenada (GoG)procured a 1,818 m 3 /day (400,000 US GPD) desalination plant to assist in augmentation ofwater supply to the southern communities, however, inadequate supply from production wellsdelayed the completion of project. NAWASA is also considering deep-well abstraction forsupply augmentation for mainland Grenada (A. Neptune pers. comm. 2006)On the sister islands of Carriacou and Petit Martinique water is drawn almost exclusively fromindividual or communal RWH systems as these islands are very arid and have virtually noperennial streams. There is 1 borehole from which groundwater is abstracted to serve the smalldowntown core of Hillsborough in Carriacou. Rainwater also finds uses in other sectors such asagriculture, construction and tourism. In 1998 the Government of Grenada invested indesalination plants for both Carriacou (100,000 US GPD output capacity) and PetitMartinique (30,000 GPD output capacity). The former is plagued with regular mechanicalfailures, while the latter, since the passage of hurricane Ivan has been non-functional. A fewhotels and resorts (e.g. in Culligen) have small desalination plants to augment their watersupplies (CEHI, 2006).RWH is practiced to a small degree on mainland Grenada but more so by households incommunities particularly in the south of the island where there are serious supply problems. Ingeneral, the practice has become less common as NAWASA’s distribution has expanded toservice almost all communities on the island. By contrast, RWH is of paramount importance inCarriacou and Petit Martinique where communal and private systems supply almost 100% ofdemand. There are no specific policies or legislative provisions to support RWH in Grenada.JamaicaJamaica exploits over 400 ground and surface water sources where the estimated dailyproduction is 913 MCM (million cubic metres) per day. More than 70% of the country’s watercomes from ground water sources (NWC, 2003). The public water supply system operated bythe National Water Commission presently services 72% of the population. While Jamaica hassufficient water to meet all demands, the resources are unevenly distributed in both time andlocation. The present shortfall is estimated at 400 MCM/yr (GoJ, 1999). Roughly 30% of waterabstracted goes to domestic purpose while 70% goes into non-domestic purpose which includesagriculture.The large landmass combined with the topography, hydrologic and economicconsiderations present challenges to realization of 100% coverage, and isolated communitiesneed to rely on small water supply systems whether from catchment tanks, truck deliveries or14
Caribbean Rainwater Harvesting Programmesurface sources. In some rural areas, small scale rural water development companies(registered as Benevolent Societies) have been established to operate water productionsystems. Development planning is closely linked to availability or access to water. Waterdemand for developments in rural areas is calculated at 150 litres/person/day and the percapita urban water demand is 172 litres /person/day.RWH systems are common in areas where there is no reliable public water supply and in areaslacking access to river, spring or well water sources. It is estimated that more than 100,000Jamaicans depend on RWH as the primary source of water (UNEP/OAS, 1997). In some of thenew housing areas established on reclaimed lands from abandoned bauxite operations such asin Claremont, St. Ann; RWH systems are the primary sources of potable water. In theaftermath of Hurricane Ivan in 2004, RWH was extensively employed by various publicinstitutions that were affected by supply interruptions. In communities where RWH ispracticed, the Environmental Health Department (EHD) educates persons in systemmanagement and sanitation, and routine water quality monitoring is carried out. In addition,the EHD regulates the design and materials for use in RWH systems.The Water Resources Authority (WRA), the agency responsible for the management,protection, and controlled allocation and use of Jamaica’s water resources advocates the use ofrainwater harvesting techniques in areas lacking access to river, springs or groundwaterresources and also to augment the public water supply system during period of water scarcity.St. Kitts and NevisMost of St. Kitts’ water demands is met by ground water although prior to 1970, surface waterwas the dominant source. The coastal aquifers are divided into seven major ground waterbasins with an estimated total safe yield of 50,000 m 3 /day (11 MGD) of which about 27,300m 3 /day (6 MGD) has been developed to meet current demands.There are some twenty-five (25) ground water wells while the average demand from thesewells is about 18,200 m 3 /day (4 MGD). In addition there are six surface water intakes thatyield about 9,000 m 3 /day (2 MGD). There are about five independent distribution systemswith inter-linkages for redundancies.In Nevis ground water accounts for 80% of the public pipe-borne supply, and surface wateraccounts for the remaining 20% (UNACE, 2004). The St. Kitts Water Services Departmentestimates 98% coverage to users in St. Kitts and 90% for Nevis. There are two privately-owneddesalination plants in St. Kitts with capacities of 3,600 and 5,500 m 3 /day (0.8 and 1.2 MGD).There are no desalination plants on Nevis.There is growing concern over protection of the aquifers from impacts related to sea level riseand saline intrusion given the relative scarcity of freshwater resources. Abstraction rates mustbe carefully controlled along with judicious management of land resources to control potentialpollution risk (USACE, 2004).Rainwater harvesting is more common in Nevis where it is estimated between 80 to 90% ofresidents and businesses have capacity to capture rainwater. In St. Kitts it is estimated that 5%of the population practices RWH.15
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A programme for Promoting Rainwater Harvesting in the Caribbean

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